Harden local debug runner cleanup for stale processes and locked logs

[Cataldir]

Context

VS Code debug startup can fail when a previous local Tutor process keeps .tmp/local-dev/logs/*.out.log or *.err.log open. The observed failure was Remove-Item on �vatar.out.log because the file was being used by another process.

Scope

• .vscode/scripts/local-dev.ps1
• Local development/debug workflow only.

Acceptance criteria

• start and restart clean safe stale Tutor processes before reusing logs.
• Cleanup is constrained to local Tutor dev ports and workspace command lines.
• Locked log files no longer fail startup; the runner removes or rotates logs safely.
• pids.json stays flat and status/stop tolerate stale or invalid records.
• Chat debug lifecycle validates: start, health, debug port listen, flat PID state, stop, ports clear.

Implementation status

Implemented in the current workspace and validated locally.

Validation

• PowerShell parse: PASS.
• VS Code JSON diagnostics: PASS.
• Chat debug lifecycle: PASS.
• Final Tutor local ports: clear.